1. Resistors for electronic circuits are manufactured on a high-speed automated
ID: 375986 • Letter: 1
Question
1. Resistors for electronic circuits are manufactured on a high-speed automated machine. The machine is set up to produce a large run of resistors of 1,000 ohms each. To set up the machine and to create a control chart to be used throughout the run, 6 samples were taken with four resistors in each sample. The complete list of samples and their measured values are as follows: Determine the UCL and LCL for a chart. Determine the UCL and LCL for R-chart. (Please round to 2 decimal places)
Sample Number
Observations
Mean
Range
1
2
3
4
1
31
45
27
35
2
28
20
33
28
3
28
32
36
30
4
12
28
23
25
5
40
32
38
36
6
45
46
33
40
a. R chart UCL=28.89; X-bar Chart UCL = 41.38.
b. R chart UCL=12.67; X-bar Chart UCL = 22.88.
c. R chart UCL=0; X-bar Chart UCL = 41.38.
d. R chart UCL=22.88; X-bar Chart UCL = 12.67.
2. From Problem 1, Resistors for electronic circuits are manufactured on a high-speed automated machine. The machine is set up to produce a large run of resistors of 1,000 ohms each. To set up the machine and to create a control chart to be used throughout the run, 6 samples were taken with four resistors in each sample. Is the process in statistical control?
a. The process average is in statistical control.
b. The process variability is out of statistical control.
c. The process average is out of statistical control.
Sample Number
Observations
Mean
Range
1
2
3
4
1
31
45
27
35
2
28
20
33
28
3
28
32
36
30
4
12
28
23
25
5
40
32
38
36
6
45
46
33
40
Explanation / Answer
Mean = Average of observation in each sample
Range = maximum - Minimum value for each sample
X-bar-bar = (34.5+27.25+...............41)/6 = 32.13
R-bar = (18+13+..........+13)/6 = 12.67
UCL for X-bar = X-bar-bar + A2*R-bar
A2 for sample n = 4 is 0.73
UCL = 32.13 + 0.73*12.67 = 41.38
For R-bar, UCL = D4*R-bar.
For n=4, D4 = 2.28
UCL = 2.28*12.67 = 28.89
Ans A
2) C
Averag eis out of UCL
Sample Mean Range 1 31 45 27 35 34.5 18 2 28 20 33 28 27.25 13 3 28 32 36 30 31.5 8 4 12 28 23 25 22 16 5 40 32 38 36 36.5 8 6 45 46 33 40 41 13Related Questions
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